Fuel compositions



United States Patent 2,932,560 FUEL COMPOSITIONS No Drawing. Application August '30, 1955 Serial No. 531,581

2 Claims. (CI. 44-76) This invention relates to improved spark ignition engine or jet engine fuel compositions comprising a major portion of gasoline or jet fuel hydrocarbons and a minor proportion of a low molecular weight dialkyl sulfoxide,

Carburetor icing is a serious problem in the operation of spark ignition internal combustion engines. Such icing occurs as a result of vaporization of the gasoline fuel in the carburetor under certain conditions of temperature and humidity, and the icing results in such deleterious effects as plugging of the fuel inlet into the carburetor with consequent engine stalling.

Icing is also a serious problem in the operation of jet propelled aircraft. At temperatures encountered during jet aircraft flight, water which is present in the jet fuel freezes causing clogging of fuel lines and filters with resulting operational difficulties.

In practice of the present invention, carburetor icing in spark ignition internal combustion engines and icing in jet engines operation are alleviated or substantially completely overcome. Low molecular weight dialkyl sulfoxides which are substantially soluble both in water and in hydrocarbons are incorporated in the gasoline or jet fuel in minor amount. These dialkyl sulfoxides efiectively suppress or prevent carburetor icing in spark ignition internal combustion engines and icing in jet engines. The dialkyl sulfoxides used in the present invention should have a total of six or less carbon atoms per molecule in order to have sutficient solubility both in water and in the fuel hydrocarbons to suppress icing. The use of dimethyl sulfoxide is especially preferred. Other dialkyl sulfoxides which can be used are methyl vethyl sulfoxide,diethyl sulfoxide, methyl propyl sulfoxides,

ethyl propyl sulfoxides, dipropyl sulfoxides, methyl butyl sulfoxides, ethyl butyl sulfoxides, and methyl cyclopentyl sulfoxide.

The dialkyl sulfoxides used in this invention are prepared in accordance with procedures which are known in the art. Generally, such procedures involve controlled oxidation of sulfides to the desired sulfoxide. Suitable oxidizing agents are air, nitrogen oxides, hydrogen peroxide, nitric acid, and the like. Other methods known in the art for preparing dialkyl sulfoxides can be employed.

In carrying out one embodiment of the invention, the

dialkyl sulfoxides, e.g. dimethyl sulfoxide, are incorporated in minor amount sufiicient to suppress carburetor icing in gasoline hydrocarbons which are normally used as fuel in spark ignition internal combustion engines. Such hydrocarbons boil in the range of about 80 F. to 440 F., and usually in the range of about 90 F. to 400 F. The gasoline compositions of this invention can contain, in addition to the dialkyl sulfoxides and hydrocarbons, any of the fuel additives which are commonly employed in the art. It is preferred to use organemetallic anti-knock agents such as iron carbonyl, biscyclopentadicnyl iron, and particularly tetraethyl lead in the gasoline compositions of this invention. Such antiknock agents are generally used in amounts of about 0.5 to 5 cc. per gallon of fuel. scavenging agents can be used with these organo-metallic anti-knock agents. Other additives, e.g. detergents, anti-rust additives, and the like can be used to advantage in the fuel compositions of this invention together with the dialkyl sulfoxides and gasoline hydrocarbons.

The dialkyl sulfoxides are added to the gasoline hydrocarbons in minor amount sutlicient to suppress internal combustion engine carburetor icing. Generally, amounts of dialkyl sulfoxides in a range of about 0.05% to 2% by volume of the hydrocarbon fuel and preferably 0.1% to 1% are suitable to suppress carburetor icing. However, greater or lesser amounts of dialkyl sulfoxides can on occasion successfully be used. The dialkyl sulfoxides are sufliciently soluble in gasoline as not to require the use of a mutual solvent or dispersing agent.

In addition to suppressing carburetor icing, practice of this embodiment of the invention has another advantageous effect. Low molecular weight dialkyl sulfoxides are eifective solvents for carbonaceous combustion chamber deposits. When gasoline containing an anti-icing amount of dialkyl sulfoxide is used in an internal com.- bustion engine, the sulfoxide provides a continuous sol vent action on deposited carbonaceous material in engine combustion chambers with a resulting lessening in the accumulation of such deposited material.

In a second embodiment of this invention, a low molecular weight dialkyl sulfoxide, e.g. dimethyl sulfoxide, is incorporated in a jet propulsion engine fuel in minor amount sufiicient to suppress icing of the fuel during use in jet aircraft. Usually amounts of the dialkyl sulfoxide of about 0.05% to 2% by volume of the jet fuel and preferably 0.1% to 1% are sufiicient to efifectively suppress icing. Amounts outside this range can, however, be used.

The jet fuel used in carrying out this embodiment of the invention can be any of the hydrocarbon fuels of the JP-4 type conventionally employed as fuel for jet propelled aircraft. Jet fuel of the JP-4 type normally comprises hydrocarbons boiling in the range of about F. to 600 F., and has a freezing point below about --76 F. A description of the properties of jet engine fuel is given by C. W. Kelley in the November 1952 edition of The Petroleum Engineer on pages C-l to C-9. The dialkyl sulfoxides are sufficiently soluble in the jet fuel as not to require mutual solvents or dispersing agents.

The following illustrates a practice of the first-described embodiment of the invention:

Dimethyl sulfoxide is added to gasoline hydrocarbons, which hydrocarbons contain an anti-knock amount of tetraethyl lead, in amount of 0.1% by volume of the hydrocarbons. The resulting gasoline composition, when used as fuel in a spark ignition internal combustion engine, efiectively resists carburetor icing.

The following illustrates practice of the seconddescribed embodiment of the invention:

Dimethyl sulfoxide is added to JP-4 jet engine fuel in amount such that the dimethyl sulfoxide comprises 0.1% by volume of the jet fuel. This resulting composition can be used as fuel in propelling jet aircraft at lower temperatures without icing than the original JP-4 fuel.

In my copending patent application S.N. 531,580, now abandoned, filed of even date herewith, there are disclosed and claimed'methods of periodically servicing internal combustion engines to remove carbonaceous deposited material utilizing dialkyl sulfoxides. The invention claimed in said copending application is separate and distinct from that claimed in the instant application which is directed to compositions of matter comprising gasoline or jet fuel and dialkyl sulfoxide.

more thanysix carbon atoms per molecule: to suppress,

carburetor icing.

2. Composition according to claim 1 wherein said.

dialkyl sulfoxide is dimethyl sulfoxide.

References Cited in the'file of this patent UNITED STATES PATENTS Farkas Jan. 30, 1950 Smedslund Jan. 1, 1952 Goodhue eta1 Oct. 6, 1953 Thompson May 4, 1954 Sullivan et a1. Dec. 31, 1957 

1. SPARK-IGNITION INTERNAL COMBUSTION ENGINE FUEL COMPOSITION CONSISTING ESSENTIALLY OF PETROLEUM HYDROCARBONS BOILING IN THE GASOLINE RANGE AND FROM ABOUT 0.05 TO ABOUT 0.1 PERCENT BY VOLUME OF A DIALKYL SULFOXIDE HAVING NOT MORE THAN SIX CARBON ATOMS PER MOLECULE TO SUPPRESS CARBURETOR ICING. 